1. Field of the Invention
The invention relates to an apparatus for the parking of vehicles of the kind comprising at least two platforms arranged one above another and movable collectively in a substantially vertical direction to bring any selected platform into communication with a common vehicle-entry area.
2. Description of the Prior Art
The prior art discloses apparatus of this kind which are so constructed that one or more platforms with vehicles disposed thereon can be lowered into a pit beneath the point at which vehicles approach the apparatus. The uppermost platform can constitute a parking space for a vehicle when the apparatus is retracted. It is also possible to devise the apparatus in such a way that the uppermost platform, which for example may be so made as to allow for travel thereacross, can serve as a trackway for other purposes.
One known apparatus of this kind has a rail at one or both sides of the platforms with carriages movable thereon and carrying the platforms. The carriages can be moved vertically by means of a power unit. Again, means are known for tilting the platforms relatively to the carriages and the rails, with the advantage that the "lift" can be kept somewhat less than the depth of the pit. It also enables one of the ends, namely the lifted end, of a platform to be brought into communication with the entry area.
The distribution of the load to be carried by the platform is not known in advance and the rails themselves have a substantial weight, so that care is necessary in designing the rails and the carriages and the general equipment of the apparatus. The mounting in the pit normally requires a hoist mechanism and is consequently expensive and time-consuming.
A further difficulty with this known construction is that it is only with trouble that one can get all the parts into the pit in the retracted condition and leave no constructional part standing proud. This is required if for example the upper platform is to be used as a throughway. This difficulty usually arises because the depth of the pit is approximately the same as the height of lift by the apparatus so that in the case of a rail length of the order of the depth of the pit there is not adequate guidance left between the rail and the carriage. It is necessary therefore either to work with a multipartite telescopic arrangement or to provide additional depth in the pit to provide for safe mutual guidance.